one way or another, a certain group of people will be camping. right now, the zombies are camping. by taking their health slowly using a vamp tag, their life will merely stay at 1, allowing them to keep camping and just wait for a human to get close. if such a thing is not possible, itll cause more humans to camp instead.
i think the balance right now is okay considering humans have access to a much larger variety of weapons including grenades and sprays and mines, allowing them to deal with camping zombies if theyre smart enough.